…e integration tests (elastic#226759)

## Summary

This PR enables accidentally skipped prebuilt rules package integration tests.

## Details

The integration tests were accidentally skipped by missing `loadTestFile(require.resolve('./prebuilt_rules_package'));` line in elastic#225495 as the result of merge conflicts.

Enabling those integration tests revealed an issue with the installing all prebuilt rules integration tests. Since the prebuilt rules package contains ML rules all rules installation fails under the low-tier license as ML rules require high-tier license. So this single test was changed to run under high-tier license.

Just for the record, ML related UI issues has been addressed in elastic#224676. It means that users may observe this error under low-tier license only by using the API directly.

(cherry picked from commit 189cfb5)

# Conflicts:
#	x-pack/test/security_solution_api_integration/test_suites/detections_response/rules_management/prebuilt_rules/common/index.ts